For the past couple of months, I've been noticing something very strange about my 8. It has noticeably more torque and idles better when I'm below 1/4 tank of gas. It's noticeable enough where I'll get in the car and once it's warm and I've been driving for a few minutes, I'll take off from a light driving like I normally do (shifting at 4-5k) and I'm like "Damn it's pulling hard today" and then I'll think to look at my gas gauge, and sure enough, it'll be below 1/4. It's not that it runs poorly the rest of the time, I can just tell a difference and it bugs me. Like enough to just drive around below 1/4 all the time

Any ideas? I'm thinking it could possibly be a weak fuel pump, but it should be the complete opposite scenario if that was the case....

I'm getting like 200 miles/tank city and 250-260 hwy. I premix 6-8oz/tank as well. It happens even if I don't premix though.

 

less weight due to less fuel?

 

Hi CJ,
I thought driving under 1/4 tank was risky.
I read about overheating fuel pumps, and fuel starvation on hi-G left turns.

 

Maybe...but it's a night and day difference. It doesn't run better at 1/2 than it does full. Just better below 1/4 period...

Yeah, what you say is true. I don't have any issues though, quite the opposite haha.

 

I would say it is leaning out a little more with less fuel and your picking up some of the pre mix from the bottom of the tank which did not mix well. not rx8 related but my weed wacker does the same thing when it is running low on fuel, it revs higher and just runs better.

 

The 'Weedwacker Boost"!
I like it.

 

Is that like Wacky Racers???

 

2 stroke string grass trimmers.
Don't know what a wacky racer is.
Gotta get moving, have a good one.

 

When you get back from work you can read that I was gobsmacked as I always thought "Wacky Racers"was an American cartoon TV show. Did you have a deprived childhood or was I just incredibly infatuated by cartoons. Actually, probably the last thing!!

 

This answer

http://www.imdb.com/title/tt0122365/?ref_=sr_1
Oh yes, Saturday morning cartoons, good times.

 

This crossed my mind except that it does it when I don't pre-mix as well
Pretty much the only logical answer I guess lol

Thanks everybody

 

It leans out the fuel at higher loads. The engine goes crazy rich at some loads/rpms knocking everything down to around 12.5 max will add a very noticeable increase in power.

 

Guess that's one of the ways a tune with the cobb can increase power (and probably mpg)

Man I want a cobb so bad haha